There have been known techniques of performing a session connection with a plurality of terminal devices. For example, a technique of causing the same screen to be displayed on a mobile phone and a television is discussed in Patent Document 1. In Patent Document 1, an authentication server transmits a session identifier to an information appliance according to a request, and the information appliance converts the session identifier and a device identifier into a two-dimensional code and displays the two-dimensional code on a screen. A mobile phone images the two-dimensional code, accesses the authentication server, and transmits screen data delivered to the portable electronic device to a specified information appliance based on a screen sharing table when user authentication is completed.